Waves Basics

Question 0

What is displacement of a wave and what is it’s symbol?

Answer 0

Displacement, X , measures how far from its equilibrium position a point in the wave has moved.
Usually the y axis on a wave diagram.

Question 1

What is a progressive wave?

Answer 1

A wave that carries energy without transferring any material. Caused by oscillation of particles in a medium.

Question 2

In terms of measuring waves, what is X and what is it measured in?

Answer 2

Displacement measures in meters

Question 3

What is a waves amplitude and what is its symbol?

Answer 3

Symbol: a

It is he maximum displacement of a wave. The max movement from the equilibrium position to a trough or crest.

Question 4

What is a waves wavelength and what is its symbol?

Answer 4

Symbol: lander

It is the length, in meters in one complete wave cycle or oscillation. E.g the distance between to crests.

Question 5

What does the symbol a stand for and what is it measured in?

Answer 5

Amplitude measured in meters

Question 6

What does the lander symbol stand for and what is this measured in?

Answer 6

Wavelength measured in meters.

Question 7

What is the period of a wave? What is its symbol?

Answer 7

Symbol: T

This is the time in seconds, for 1 complete cycle or oscillation to take place. E.g time between two crests

Question 8

What is a waves frequency and what is its symbol?

Answer 8

Symbol: f

Measured in Hz, frequency is the number of cycles or oscillations per second.

Question 9

What is a waves phase difference? What is it measured in?

Answer 9

This is the difference between to identical points in two different waves. The amount one wave lags behind another.

Mesured in degrees or radians

Question 10

What equation links frequency and a waves period?

Answer 10

Frequency = 1/period 
f= 1/T

Question 11

What are two equations to find a waves speed?

Answer 11

C=f x lander

C = distance/time

Question 12

Is phase difference the same as

Path difference?

Answer 12

NO

Question 13

What is path difference and what is it measured in?

Answer 13

The amount by which the path travelled by one wave is longer than the path travelled by another wave.

Measured in wavelengths or meters

Question 14

Which waves oscillate at right angles to the direction of travel or the wave?

Answer 14

Transverse waves

Question 15

What type of waves are electromagnetic waves?

Answer 15

They are transverse waves.

Question 16

What are transverse waves?

Answer 16

They are waves that the vibrations are at right angles to the direction if travel.

Question 17

Examples of transverse waves are

Answer 17

All electromagnetic waves
Water ripples
Waves on ropes
String instruments

Question 18

What are the two ways of representing transverse waves?

Answer 18

Displacement against distance graphs,

Displacement against time for a point as the wave passes.

Question 19

Longitudinal waves are …

Answer 19

Waves that have vibrations along the direction of travel.

Question 20

Waves that oscillate along the direction of travel are called?

Answer 20

Longitudinal waves

Question 21

What type of wave is sound

Answer 21

Longitudinal

Question 22

In a longitudinal wave what are crests and troughs called?

Answer 22

Compressions and rarefractions

Question 23

Examples of longitudinal waves are

Answer 23

Sound
P- waves in earthquakes
A slinky on a table that is knocked at one end.

Question 24

What is a polarised wave?

Answer 24

A wave that only oscillated in one plane or direction.

Question 25

How do polarising filters work.

Answer 25

Light is a mixture of different polarisations.
A polarising filter only allows through oscillations in a certain direction.
The light that gets through is polarised the same way.

Question 26

How can two polarised filters be arranged to not allow light through?

Answer 26

They should each only allow light through that is at a right angle I the other filter.

Question 27

How do polarised googles or sunglasses work?

Answer 27

When light is reflects of some surfaces it becomes partially polarised.
Polarised Filters in the glasses can filter out this light to prevent glare from the surface.

Question 28

How can polarisation improve tv or radio signals.

Answer 28

The radio waves are polarised by he orientation of the rods transmitting them.
To get a good signal the receiving Ariel should be aligned the same.
That’s why having tv Aries are horrizontal.

Question 29

Uses of polarising lenses.

Answer 29

Sunglasses
Photography
Experiments.